This invention relates to the routing of telecommunications, and in particular to improving reliability in the connection between an end-user and the network to which the user is connected.
Telecommunications services such as voice, data, video etc may be provided to a customer by any of several different means, for example by a broadband connection to the “Internet”, typically over the traditional “copper pair” fixed-line connection originally deployed for simple voice telephony, or the more recent fibre optic cable connections, or a wireless connection. Wireless communications systems are more versatile than fixed lines, in that connections can be readily reconfigured to cope with mobile users, changes in demand, or infrastructure failure. Although installation is simpler, the ongoing cost of providing a wireless system is much greater than for a fixed connection of similar capacity.
Recent trends have been to integrate many different services over a single physical connection, rather than using separate connections for each one. This method of provisioning is more cost-effective and versatile than separate provisioning for each service, but it leaves the user vulnerable to simultaneous loss of all services in the event of a failure of that connection. Large business customers can afford to provide multiple redundancy in their physical connections to ensure continuity of service, but such arrangements are too costly to be economic for smaller businesses and domestic users: Examples of such systems are discussed in Patent specifications US2005/0008017, US 2003/0031180 (both Datta et al), and U.S. Pat. No. 6,144,641 (Kaplan et al).
According to the invention, there is provided a telecommunications network having provision for communications addressed to a given network termination device to be routed to a primary network address, means for associating a secondary network address with the primary network address, monitoring means for detecting a loss of connectivity between the network and the primary network address, and means for causing the network termination device to connect with the network over a secondary routing using the secondary network address when such loss of connectivity is detected.
The invention also provides a co-operating telecommunications network termination device having user device connection means for connection to one or more computing devices, and at least two network connection means, the first network connection means having a first network address for communicating with a network by way of a primary routing, and a second network connection having means for communicating with a network using a second network address by way of a secondary routing, further comprising monitoring means for identifying a failure of communication with the network by the first connection means, and means for diverting connection to the secondary connection means using the second network address when such failure is detected.
The invention also provides a method of operating a telecommunications system in which connection between a network termination device and a network may be made by means of a primary routing having a first network address or by an alternative, secondary routing, having a second network address, between the termination device and the network, and wherein if a failure is detected in the primary routing, the termination device generates a message to the network to cause traffic to and from the termination device to be diverted over the secondary routing using the second network address.
In a typical installation the primary routing would be a dedicated fixed line connection and the secondary routing would be provided by a wireless distribution point associated with a plurality of fixed line terminations. As it is unlikely that all the fixed line connections would fail at the same time, the wireless distribution point need only have capacity to support one, or a limited number, of the primary connections.
Preferably, on initial connection being established between a network termination device and a first connection, a signal indicative of the capability of the network termination device to be connected by way of an alternative routing is transmitted over the first connection, and on receiving this signal the network control system retrieves, from an associated store of network topology data, network address data relating to at least one secondary network routing, and transmits the network address data to the user termination device. Thus the termination and the network co-operate to identify a capability to set up an alternative routing, and identify a suitable routing if this is the case.
Preferably, the telecommunications network termination device has means to generate an address update in response to instructions received from the network indicative of a failure of the first connection means. This allows transmissions to the termination to be diverted to the new network address using standard address update procedures common in mobile access systems.
Preferably, attempts are made to continue transmission of the monitoring signal over the primary routing whilst traffic is diverted over the secondary routing, and if the monitoring signal transmitted over the primary routing is again detected by the network control system, indicating that such connection has been restored, traffic is redirected over the primary network using the first network address.
The device preferably has means to monitor the secondary route to ensure that it too is working and intact. In the preferred embodiment the device generates connection integrity messages for transmission by way of the connections, and means to respond to diversion instructions received from the network in the event that the network fails to receive them.
In the embodiment to be described, the connections are of ADSL (asymmetric digital subscriber line) type, but this is not limitative of the scope of the claims.
The user device connection means may provide fixed or wireless connection to a number of individual computing devices, for example through a local access network (LAN) or a wireless local access network (WLAN).
In co-operation with such a device, the telecommunications network includes provision for arranging for communications addressed to a given user to be routed either to a fixed line termination or to a wireless distribution point associated with the fixed line termination.
Preferably the wireless distribution point is associated with a plurality of fixed line terminations. The wireless connection may therefore be available to a plurality of users, each having a similar hub device. As it is unlikely that more than one or two of the users would require this capacity at the same time; the wireless distribution point can act as a reserve link for many such terminations, making the provision of a large capacity reserve link viable. This allows the cost of provisioning the required capacity to be shared between several users, offering some economies. Consequently, several businesses on neighbouring sites, for example in a business park, may share the use of the distribution point. Each user would have a primary broadband connection via the normal copper pair delivery network, and a secondary broadband route via a wireless connection between the hub device and the shared wireless distribution point serving the business site.
The hub device has means to redirect the wireless and physical LAN traffic over the secondary route until the primary route is repaired. When a failure of the primary route is detected, the user can be reconnected onto the shared wireless route to provide a connection whilst repair of the primary route is carried out. The network has means for detecting traffic received from users by way of the distribution point, and means for redirecting traffic destined for that user so that it is routed by way of the wireless connection.